An emergency stop cover with plug-in unit includes a lock cover and lock, a lock base having a lockstitch, a stop button, a locking tongue in front end of the lock inserted into a lockstitch for connecting the lock cover to the lock base when the emergency stop cover is in its locked position. Because plug-in units are not available for existing emergency stop covers, users of stop covers need another locking means to ensure that the emergency stop button will not open when the stop button is depressed.
In addition, many existing emergency stop buttons have a locking tongue in the front end of a shutter that projects out through the stop button. The stop cover opens by directly pushing the shutter at the time when it is not locked with a lock. As such, existing emergency stop covers are not convenient and safe to use.